Extruding apparatus for extruding stepped products

Abstract

An apparatus for extruding stepped extrusions, e.g. of aluminium or aluminium alloy, comprises a die holder (16a) carrying a major die (19), and a split minor die (18) arranged for abutment with the downstream side of the major die (19) and having its two halves mounted on respective parts of a split holder (17). The holder parts are movable towards and away from the line of extrusion to put together and separate the halves of the minor die (18). The die holder and the container (12) of an extruder are movable towards each other to press the minor die (18), the major die (19) and the downstream face of the container (12) into sealing engagement about the die apertures, and are movable away from each other to permit the extrusion to be sheared off between the container (12) and the major die (19).

We claim: 
     
       1. An extruding apparatus comprising a die block in one end of which is formed a recess for receiving a major die, a major die having a front or upstream face and a rear face mounted in said recess, a sectional holder for a minor die, a minor die carried by said sectional holder and having a front face and a rear face formed in two or more sections, which die sections jointly define the full periphery of the die aperture of the minor die, the sections of the holder being adapted to locate the respective sections of the minor die in aligned relative positions and in axial abutment with the downstream or rear face of the major die, said sections of the holder for the minor die being mounted in the die block for movement selectively to bring the minor die sections into said aligned relative positions and to separate the minor die sections and move them outward away from each other and from a line of extrusion extending through said major die, and means for so moving the said sections of the holder. 
     
     
       2. Apparatus as claimed in claim 1, wherein the said sections of the holder are mounted for linear sliding movement in slideways formed in the die block and extending generally radially with respect to said line of extrusion. 
     
     
       3. Apparatus as claimed in claim 1, wherein the front or upstream face of the major die is arranged for abutment with a rear end face of an extrudant container to form a seal with said rear end face of the container, so as on termination of extrusion to enable extrudant discard to be sheared off at the front face of the major die. 
     
     
       4. Apparatus as claimed in claim 1, wherein the front face of the minor die projects a small axial distance into the recess for the major die and the major die is secured in said recess by means permitting the major die a small degree of lost motion away from the minor die. 
     
     
       5. An extruding apparatus including an extruder comprising a container having a rear or downstream end face, a die block having a front end face disposed facing said rear end face of the container, a recess in said front end face, a major die disposed in said recess coaxially with the container and arranged to protrude from the recess for abutment with the rear end face of the containers, a minor die formed in a plurality of sections, a die holder formed in a plurality of sections in which the minor die sections are respectively mounted, means for moving the die holder sections towards and away from the line of extrusion to place the minor die sections together and to separate them, the minor die sections when together protruding a small distance into said recess and abutting axially against the face of the major die farthest from the container, means for relatively moving the container and the die axially towards and away from each other to move the front end face of the major die into and out of the abutment with the rear end face of the container, and a shearing blade operable to move between the major die and the container when said major die and the container are out of abutment to shear off an extruded length.